Yellowstone ecosystem could lose key migrant species

The pronghorn antelope -- a key species in the Yellowstone ecosystem -- travels more than 400 miles between its fawning grounds and wintering areas, making it one of the most well-traveled species in North America. But with six of its eight migratory paths already lost to human development, the pronghorn faces an uncertain future if its remaining migration routes are not protected, according to a study published this week in Biology Letters.